Physical Sciences and Mathematics Commons^™

Inventory Of Rock Glaciers In The American West And Their Topography And Climate, Allison Reese Trcka

Dissertations and Theses

Rock glaciers are flowing geomorphic landforms composed of an ice/debris mixture. A uniform rock glacier classification scheme was created for the western continental US, based on internationally recognized criteria, to merge the various regional published inventories. A total of 2249 rock glaciers (1564 active, 685 inactive) and 7852 features of interest were identified in 10 states (WA, OR, CA, ID, NV, UT, ID, MT, WY, CO, NM). Sulfur Creek rock glacier in Wyoming is the largest active rock glacier (2.39 km²). The mean area and elevation for active and inactive rock glaciers are 0.18 km², 3384 …

Distribution, Geochronology, And Petrogenesis Of The Picture Gorge Basalt With Special Focus On Petrological Relationships To The Main Columbia River Basalt Group, Emily Bogdan Cahoon

Dissertations and Theses

The Columbia River Basalt Group (CRBG) is the youngest and volumetrically smallest continental flood basalt exposed across the Pacific Northwest, USA. Similar to other large igneous provinces, the majority of material erupted during the initial 1 million years of activity, these lavas are subdivided into four main-phase units. The Picture Gorge Basalt (PGB) is the only main-phase unit of the CRBG whose age is not precisely known and understanding of PGB petrogenesis is largely based on a limited number of samples when compared with other main-phase units. It is suggested that a time gap of over 0.5 myr existed between …

Testing The Correlation Of Trace Element Characteristics With The Petrology And Temperature Of Eruption Of Mid-Miocene Rhyolites In Eastern Oregon, Brianna Christine Young

Dissertations and Theses

The Lake Owyhee Volcanic Field (LOVF) in eastern Oregon experienced several major eruptive events during the mid-Miocene (16.8 to 15.5 Ma), resulting in the emplacement of 3,900 km³ of rhyolitic lava flows and ash-flow tuffs. Eighteen samples from eleven different silicic centers in the LOVF were selected for this study. While all samples of this study are classified as rhyolite, their compositions vary greatly in terms of trace and major elements. Using trace elements, these rhyolite samples are classified as "A-type", described as resulting from "hot and dry" magmas and associated with hot-spot activity, or as "I-type" or "calc-alkaline", …

The Rocky Ledge Fault, Shasta County, Ne California: Development And Morphology Of A Quaternary Oblique Normal Fault In Basalt, Gregory David Linscott Martin

Dissertations and Theses

Distinct morphology, variable vertical separation, and unique structural geometries are observed along the Rocky Ledge fault (RLF), an east-dipping, oblique normal fault in the tectonically complex Hat Creek Graben, Shasta County, NE California. Situated in the southern Cascade arc, the RLF is located at the boundary of the Klamath Mountains, Basin and Range, and Walker Lane Seismic Belt. The primary goal of this project is to better understand Quaternary deformation along the RLF. I developed detailed maps of geologic units and structures along the ~15 km length of the RLF. Map data informs assessment of fault geometry, scarp morphology, and …

Geochemical Response To Thermal Energy Storage In The Columbia River Basalt Aquifer System Beneath The Portland Basin, Oregon, Ellen Elizabeth Svadlenak

Dissertations and Theses

Deep direct use thermal energy storage (TES) is a low carbon emission method of geothermal energy storage and supply for large-scale residential, commercial, and manufacturing heating and cooling. The process entails repeated cycles of hot- or cold-water injection, storage, and extraction from slow groundwater flow zones within the deeper layers of an aquifer system. Though a promising technology, TES cycles may increase mineral dissolution and precipitation reactions, particularly at elevated temperatures. The ensuing mass transfer can form scale in heat exchange systems and alter aquifer porosity and permeability, processes that can reduce the operational efficiency of a TES system.

Within …